Chinese Gender Calendar and Predictor

Updated on 14 October 2026 · Fertilio Editorial Team

The Chinese gender calendar predicts from two values whether you will have a boy or a girl: the mother’s lunar age at conception and the lunar month in which the baby was conceived. The Chinese gender predictor above converts your date of birth and the month of conception into the Chinese lunar calendar and reads off the matching cell in the chart. Large studies with almost 2.9 million births in total show that the calendar is right about every other time, just as often as a coin toss.

How to read the calendar

The chart has 28 rows and 12 columns. The rows are the mother’s lunar age from 18 to 45, and the columns are the 12 months of the Chinese lunar year. Where row and column meet, it says boy or girl.

1. Find your lunar age: In the Chinese way of counting, you are 1 year old at birth and turn a year older at every Chinese New Year, not on your birthday.
2. Find the lunar month: This is the month of the lunar calendar in which conception took place. It begins with a new moon and shifts relative to our calendar months every year.
3. Read the result: Row for lunar age, column for lunar month.

An example: You were born on 10 May 1994, and conception falls on 20 November 2026. Your birth year in the lunar calendar is 1994, and the year of conception is 2026. Your lunar age is 2026 minus 1994 plus 1, so 33. 20 November 2026 falls in the 10th lunar month. Row 33, column 10 shows girl.

If you only know the month, the calculator shows you both results when a lunar month changes in the middle of that month. With the due date, the calculator works back to conception: by calculation, it falls 266 days before the due date. After IVF or ICSI, you know the exact day; there, the day of egg retrieval counts.

Calculating your lunar age

Your lunar age (in Chinese 虚岁, xūsuì) is almost always higher than your age as we count it, usually by one year, and by two years between Chinese New Year and your birthday. The formula is: lunar year of conception minus lunar year of your birth plus 1.

Chinese New Year is what matters. If you were born in January or February before Chinese New Year, you still belong to the previous lunar year. The same applies to a conception in January or early February.

Lunar months 2026 and 2027

Each lunar month begins with a new moon and lasts 29 or 30 days. Twelve lunar months are about 11 days shorter than our year. So that the lunar year does not drift through the seasons, it gets a 13th month every two to three years: the leap month. In 2025, this was a second 6th month, and in 2028 it will be a second 5th month. The dates come from the official conversion tables of the Hong Kong Observatory.

The chart has no column of its own for the leap month. The calculator follows the common rule: days 1 to 14 of the leap month count toward the month before, and from day 15 the following month applies. There is no evidence for this rule; it is a modern convention among online calculators.

Fact check: is the Chinese gender calendar accurate?

No, it is no better than chance. The largest test comes from Sweden: researchers led by Eduardo Villamor compared the calendar with 2,840,755 births from the Swedish birth register from 1973 to 2006. Their conclusion: the calendar predicts the sex no better than a coin toss (Villamor 2010).

On top of that, boys have a natural head start. In 2025, there were 105.7 boys for every 100 girls born in Germany (Destatis, the German Federal Statistical Office), which means 51.4% boys. So if you guess boy for every pregnancy, you will be right more often than the calendar.

Why do so many people still say the calendar was right for them? With two possible outcomes, any method is right in every other family. Those who were right are more likely to pass it on. With the calculator, you can check it yourself against your own children: enter their birthday as the due date.

Where does the Chinese gender chart come from?

Online, it is often said that the chart is around 700 years old and was found in an imperial tomb near Beijing. There is no evidence for this, and no museum displays the original. In China, the chart is called 清宫生男生女表, the Qing palace chart for boys and girls. The Qing dynasty ruled from 1644 to 1912. Nobody knows how the chart actually came about.

Several versions are in circulation, and they differ in many cells. The calculator uses the version that nine sources we checked show identically in all 336 cells: five Chinese sources such as hao86 and k366, and four English ones such as Prokerala. The BabyCenter version differs from it in 146 of the 336 cells, starting from lunar age 23.

Ramzi theory, Shettles, and other methods compared

Ramzi theory

The Ramzi theory goes back to an article by Saad Ramzi Ismail that appeared in June 2011 on the website obgyn.net, without peer review by a medical journal. He described 5,376 pregnant women: according to him, if the placenta lies on the right on ultrasound from the 6th week of pregnancy, it will be a boy; if it lies on the left, a girl. The hit rate was reportedly 97%.

Nobody has confirmed this. A study from Iraq with 67 pregnant women found no link between the position of the placenta and the baby’s sex (Qasim 2022). In 2020, the successor website of obgyn.net replaced the original text with a note that the method had not been confirmed by any further study. There is also a practical problem: depending on the ultrasound machine and the imaging plane, right and left are reversed in the image.

When can you really tell the baby’s sex?

• Blood test (NIPT): From about the 10th week of pregnancy, the test finds enough of the baby’s genetic material in the mother’s blood, including the Y chromosome in boys. In an analysis of 57 studies, it correctly identified boys in 95.4% and girls in 98.6% of cases (Devaney 2011).
• Ultrasound: Before week 12, the sex can hardly be seen. From week 13, experienced examiners in studies are right in 99% to 100% of cases (Odeh 2009); in everyday practice, it is usually certain from week 14.
• Germany: Under § 15 of the German Genetic Diagnostics Act (Gendiagnostikgesetz), the sex may only be disclosed after the end of the 12th week of pregnancy. The usual reading is 12 weeks after conception, which means from the 14th week after the last period. Laboratories follow the same practice for the blood test.
• Switzerland: The Federal Act on Human Genetic Testing (Art. 17 GUMG) allows disclosure after the end of the 12th week from the start of the last period.
• Austria: There is no week limit for disclosure.

Frequently asked questions

How accurate is the Chinese gender calendar?

About as accurate as a coin toss. A Swedish study of 2.8 million births found no predictive value (Villamor 2010), and in the USA, the calendar was right in 50.2% of 38,394 births (Katz 2009).

How do I calculate my lunar age?

Lunar year of conception minus lunar year of your birth plus 1. The lunar year begins with Chinese New Year in January or February. The calculator above does this automatically.

Which lunar month is it now?

After you enter your details, the calculator shows you the current lunar month and the next 11, each with its start and end. All lunar months of 2026 and 2027 are also listed in the table in the section Lunar months.

Can I use the Chinese lunar calendar to plan my baby’s gender?

In terms of the calculation, yes: the preview shows you boy or girl for the next 12 lunar months. But because the calendar is no better than chance, the timing does not change the result. For family planning, what counts is the fertile window, which the Ovulation Calculator shows you.

Does the calendar also work after IVF or ICSI?

You can use it for the calculation in exactly the same way. Conception is the day of egg retrieval, and for a frozen embryo transfer, it is the transfer day minus the age of the embryo. The IVF Due Date Calculator works out the matching due date.

From which week is the doctor allowed to tell you the sex?

In Germany, after the end of the 12th week of pregnancy, which is usually read as 12 weeks after conception, so from the 14th week after the last period. This is set out in § 15 of the Genetic Diagnostics Act, for ultrasound and the blood test alike. In Switzerland, the 12th week from the last period applies.